The invention relates to a means for heating a building or for heating hot water for the building comprising in part a means adapted to use the heat from an open wood-burning fireplace. In the past, it has been generally known to use the heat from a fireplace to heat water passed around the open fire -- such as shown in U.S. Pat. Nos. 219,978, 670,066, 1,352,371, 1,432,538, and 2,113,896 -- however, none of these systems has been useful as an auxiliary in homes with conventional heating or hot-water heating systems, nor have any of these devices provided as great an area for heat transfer as the device of the present invention.
With depletion of our natural resources of oil and natural gas, and with increasingly higher electricity prices it is becoming more and more practical to use wood burned in an open fire as a heat source. In addition to having the potential of meeting a large portion of a home's heating requirements, open wood-burning fireplaces are decorative and often serve as a focal point for family activities. However, it is usually impractical to assume, as have many prior art devices, that wood burned in an open fireplace can provide all the heating or hot-water heating requirements of a home since a fire must be constantly attended to and since large quantities of wood are impractical to store in most homes and locations. However, according to the teachings of the present invention, such a fireplace if hooked up with the conventional heating (including a forced-air system) or forced hot-water heating systems of a home can supply a good deal of auxiliary heat, and can thereby save on utility bills and reduce consumption of difficult to obtain natural resources while providing aesthetic appeal as well.
According to the heating system of the present invention, a water jacket is utilized for circulating water directly around an open-hearth fire. The jacket may comprise a double-walled member having chambers disposed on five sides of the fire and having log-supporting water conducting pipes, or a grate member having water-conducting pipe portions for supporting wood thereon, in each case the wood-supporting members slanting slightly upwardly to create a convectional force so that no pinging sound results from the circulation of water through the wood-supporting members when a fire is burning. Water coming in through an inlet is circulated through the jacket and absorbs heat from the fire burning within the fireplace, and then the hot water by convection rises to the discharge area and passes out a water outlet. The bottom chamber of the multi-water chamber version of the jacket, has an opening formed therein in order to provide combustion air to the fire and increases the heating capability thereof, while additionally reducing materials expense, without interfering with water circulation through the jacket. The opening preferably is connected to the outside of the area to be heated (exterior wall) so that make-up air for the fire is provided from the outside, and not by air preheated by the conventional heating system. A damper may be provided over the combusion air opening for controlling the amount of combusion air that is admitted thereby.
The metal water jacket inlets and outlets are connected up with the conventional pipes of the heating or hot-water heating system of a building, a conventional pump circulating water from the fireplace through the radiators and water storage tank, and interconnecting pipes thereof. A means is provided responsive to the temperature within the hot water storage tank for cutting off the fuel supply (or other means essential to heating of the water by conventional means) when the temperature of water in the tank reaches a certain level due to heating thereof by the fireplace. In addition, means may be provided for cutting out the fireplace from the water circulating system when it is not desired to use the fireplace, or else the fireplace may be left in the system to act as a radiator. The fireplace may be hooked up with solar heating systems, gas burning ones, fuel oil ones, or electric heating systems, and means may be provided for modifying the system to provide forced air heating instead of water heating. For instance, the jacket can communicate with a heat exchanger disposed in the cold air return of a conventional forced air furnace, a circulating pump, expansion tank, and pressure relief valve also being associated therewith. It will be seen that according to the present invention a wood-burning heating system is provided that is in integral operative conjunction with any type of conventional heating system except baseboard electric.